JP2013146919A - Foam molding member and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam molding member that can efficiently be manufactured at a relatively low cost, while improving an impact absorbing performance, and to provide a method of manufacturing the same.SOLUTION: A foam molding member 1 comprises a foamed synthetic resin. In the foam molding member 1, a high density part H is provided which has a partially increased density of the foamed synthetic resin. The foam molding member 1 has the high density part H comprising the foamed synthetic resin of the same composition as that of other parts.

Description

  The present invention relates to a foam molded member made of a foamed synthetic resin and a manufacturing method thereof, and more particularly to a foam molded member suitable for an impact absorbing material for automobile interior and a manufacturing method thereof.

  A shock absorber made of foamed synthetic resin such as rigid polyurethane foam is attached to a door trim of an automobile for absorbing energy (EA) during a side collision (side collision).

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-154116), the impact absorbing performance of this shock absorbing material is improved by applying a synthetic resin to the surface of the shock absorbing material made of a synthetic foam resin to form a coating layer. It is described to improve. In Patent Document 1, as a method of forming this coating layer, spray coating of the surface of the shock absorbing material with a synthetic resin solution in a molten state, and immersion of the shock absorbing material in the synthetic resin solution in a molten state Have been described. In the embodiment of Patent Document 1, a non-foamed molten polyurethane resin is used as the synthetic resin liquid.

JP 2007-154116 A

  In Patent Document 1, it is necessary to apply a synthetic resin liquid to the surface of the main body portion after molding the main body portion of the shock absorber. Therefore, the manufacturing work of the shock absorbing material becomes complicated, and the next process cannot be started until the synthetic resin liquid is cured, resulting in low manufacturing efficiency of the shock absorbing material.

  In Cited Document 1, since it is necessary to prepare a foamed synthetic resin raw material for forming the main body portion of the shock absorber and a synthetic resin liquid for forming the coating layer, the material cost increases.

  An object of the present invention is to solve such problems and to provide a foam molded member that can be efficiently manufactured at a relatively low cost while improving shock absorption performance, and a method for manufacturing the same. And

  The foam-molded member of the present invention (Claim 1) is a foam-molded member made of a foamed synthetic resin, wherein the density of the foamed synthetic resin is at least partially on the inside of the foam-molded member. A high-density part that is higher than the other parts to be removed is provided, and the high-density part and the other part of the foam-molded member are composed of the same synthetic foam synthetic resin. To do.

  The foam molded member according to claim 2 is the foam molded member according to claim 1, wherein the foam molded member is a surface layer formed along at least a part of an outer surface of the foam molded member. The surface layer and the inner layer are each formed by foaming a foamed synthetic resin raw material of the same composition in a mold, and One of the surface layer and the inner layer is formed before the other layer, and when the other layer is molded, the one layer that has been molded is inserted, The layer and the inner layer are integrated, and the high-density portion is composed of a skin layer formed on the surface of the one layer when the one layer is molded.

  According to a third aspect of the present invention, in the foam molded member according to the second aspect, the thickness of the surface layer is 15 to 25 mm.

  A foam molded member according to a fourth aspect of the present invention is the foam molded member according to any one of the first to third aspects, wherein the foam molded member is made of urethane foam.

  A foam molded member according to a fifth aspect of the present invention is the foam molded member according to any one of the first to fourth aspects, wherein the foam molded member is a shock absorbing material for automobile interior.

  A method for producing a foam molded member according to the present invention (Claim 6) is the method for producing a foam molded member according to any one of Claims 1 to 5, wherein the foam molded member is molded in the molding step of the foam molded member. The high-density portion in which the density of the foamed synthetic resin is partially increased is provided inside the molded member, and the high-density portion and the other portion of the foamed molded member are configured by the same synthetic foamed synthetic resin. It is characterized by this.

  The method for producing a foam molded member according to claim 7 is the method according to claim 6, wherein the foam molded member is the one according to any one of claims 2 to 5, and in the molding step of the foam molded member, A first layer forming step of forming the one of the surface layer and the inner layer before the other layer; and inserting the formed one layer to form the other layer; A second layer molding step of integrating the surface layer and the inner layer, and in the first layer molding step and the second layer molding step, the surface layer and the inner layer are respectively the same synthetic foamed synthetic resin The raw material is molded by foaming in a mold.

  In the foam-molded member of the present invention (Claim 1), the high-density portion is provided inside, and the foam-molded member is reinforced by the high-density portion, so the high-density portion is provided inside. Compared to a foam molded member that is not formed, the shock absorbing performance is excellent.

  In the foamed molded member of the present invention, the high-density part and the other parts are composed of the same synthetic foamed synthetic resin. Therefore, in order to improve the impact absorbing performance of the foam molded member, it is not necessary to prepare a member or material different from the foam molded member itself, and the foam molded member can be manufactured at low cost. Further, in the foam molded member of the present invention, a high density portion is provided in the inside thereof, and it is not necessary to provide a covering layer for reinforcement after the foam molding process. Since the next step can be started immediately after the foam molding step, the production efficiency is high.

  In addition, at the time of molding of the foam molded member, by supplying a large amount of foam synthetic resin raw material into the mold and foaming, the resin density of the entire foam molded member is increased and the shock absorbing performance of the foam molded member is improved. However, if the supply amount of the foamed synthetic resin raw material is excessively increased, cracks may occur in the molded foam molded member. Moreover, even if the supply amount of the foamed synthetic resin raw material is increased within a range in which cracks do not occur in the foam molded member, the impact absorbing performance of the foam molded member is not improved so much.

  In addition, it is conceivable to improve the shock absorbing performance of the foam molded member by changing the composition itself of the foam synthetic resin constituting the foam molded member. It is necessary to replace the resin raw material with a new one, which increases costs. Further, if the blending of the foamed synthetic resin is changed, for example, the deformation characteristics of the foamed molded member with respect to the load at an early stage when the load starts to be applied to the foamed molded member may be changed from the foamed molded member before the blending change.

  In the aspect of claim 2, the foam-molded member has a multilayer structure comprising a surface layer formed along the outer surface of the foam-molded member and at least one inner layer on the inner side of the surface layer. . Each of the surface layer and the inner layer is formed by foaming a synthetic resin material having the same composition in a mold. In manufacturing a foam molded member, one of the surface layer and the inner layer is molded with a mold before the other layer, and then the molded one layer is inserted. The other layer is formed. A skin layer having a high resin density is formed on the entire surface of the one layer previously formed with the mold by contacting the foamed synthetic resin constituting the one layer with the inner surface of the mold. Therefore, by inserting the one layer and molding the other layer, a skin layer having a high resin density is disposed at the boundary between the one layer and the other layer, that is, inside the foam molded member. Will be. By forming the high-density portion with the skin layer, the high-density portion can be easily provided at a low cost inside the foam molded member.

  As described in claim 3, the thickness of the surface layer is preferably 15 to 25 mm. By comprising in this way, the impact absorption performance of a foaming molding member can fully be improved.

  As described in claim 4, the foamed molded member of the present invention is suitable for an impact absorbing material for automobile interior that is attached to a door trim or the like of an automobile.

  As described in claim 5, the present invention is suitable for a foam molded member whose molded body is urethane foam. For example, when the shock absorbing material of claim 4 is made of urethane foam as in claim 5, the shock absorbing material has a higher shock absorbing property.

  According to the foam molded member manufacturing method of the present invention (Claim 6), in the foam molded member molding step, a high density portion is provided inside the foam molded member, and the high density portion of the foam molded member and the others These parts are made of foamed synthetic resin having the same composition. Therefore, in order to improve the impact absorbing performance of the foam molded member, it is not necessary to prepare a member or material different from the foam molded member itself, and the foam molded member can be manufactured at low cost. Further, in the method for producing a foam molded member of the present invention, a high density portion is provided inside the foam molded member, and it is not necessary to provide a reinforcing coating layer or the like on the foam molded member after the foam molding step. Since the manufacturing process is simple and the next process can be started immediately after the foam molding process, the manufacturing efficiency is high.

  In the aspect of claim 7, the foam-molded member has a multilayer structure comprising a surface layer formed along the outer surface of the foam-molded member and at least one inner layer on the inner side of the surface layer. Each of the layers and the inner layer is formed by foaming a foamed synthetic resin material having the same composition in a mold. In manufacturing a foam molded member, one of the surface layer and the inner layer is molded with a mold before the other layer, and then the molded one layer is inserted. The other layer is formed. A skin layer having a high resin density is formed on the entire surface of the one layer previously formed with the mold by contacting the foamed synthetic resin constituting the one layer with the inner surface of the mold. Therefore, by inserting the one layer and molding the other layer, a skin layer having a high resin density is disposed at the boundary between the one layer and the other layer, that is, inside the foam molded member. Will be. By forming the high-density portion with the skin layer, the high-density portion can be easily provided at a low cost inside the foam molded member.

It is a perspective view of the foaming molding member concerning a 1st embodiment. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing of the metal mold | die which shows the manufacturing method of the foaming molding member of FIG. It is sectional drawing of the metal mold | die which shows another manufacturing method of the foaming molding member of FIG. It is sectional drawing of the foaming molding member which concerns on 2nd Embodiment. It is sectional drawing of the foaming molding member which concerns on 3rd Embodiment. It is sectional drawing of the metal mold | die which shows the manufacturing method of the foaming molding member which concerns on a comparative example. It is sectional drawing of the foaming molding member which concerns on the comparative example manufactured with the manufacturing method of FIG. It is sectional drawing which shows the method of the dynamic performance evaluation of the foaming molding member which concerns on an Example and a comparative example. It is a graph which shows the result of dynamic performance evaluation of FIG.

  Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, an impact absorbing material (hereinafter sometimes abbreviated as EA material) attached to an automobile door trim is exemplified as the foam molded member. However, the present invention is not limited to this. The present invention can also be applied to a molded member and a manufacturing method thereof.

[First Embodiment]
FIG. 1 is a perspective view of an EA material 1 as a foam molded member according to the first embodiment, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. It is sectional drawing which follows the III-III line | wire of FIG. 4 (a) to 4 (f) are cross-sectional views of a mold showing a method for manufacturing the EA material 1. FIG.

<About the structure of the EA material 1>
In this embodiment, the EA material 1 is attached to a door trim (not shown) of an automobile. In this embodiment, the lower surface of the EA material 1 in FIG. 2 faces the door trim when the EA material 1 is attached to the door trim. Hereinafter, for convenience, the door trim side (lower side in FIG. 2) of the EA material 1 is referred to as a rear end side, and the opposite side (upper side in FIG. 2) of the door trim is referred to as a front end side. The surface connecting the peripheral edges of the end surface on the rear end side (hereinafter referred to as the rear end surface) of the EA material 1 and the end surface on the front end side (hereinafter referred to as the front end surface) is referred to as a side peripheral surface of the EA material 1. The arrangement of the EA material 1 is not limited to this.

  The EA material 1 is entirely made of a foamed synthetic resin such as a rigid polyurethane foam. In this embodiment, the EA material 1 has a flat surface whose front end surface and rear end surface are substantially parallel to each other, the shape viewed from the front end side or the rear end side is substantially square, and the front end side The shape of the EA material 1 is not limited to this.

The EA material 1 is manufactured by injecting a foamed synthetic resin raw material into a mold and performing foam molding. Inside the EA material 1, a high-density portion H in which the density of the foamed synthetic resin is partially higher than other portions is provided. The high-density part H and other parts of the EA material 1 are made of the same synthetic foamed synthetic resin. That is, the entire EA material 1 is manufactured from a single foamed synthetic resin raw material. Among the EA materials 1, the density of the high density portion H is 0.03 to 0.15 g / cm ^3, particularly 0.05 to 0.13 g / cm ³ , and the surface of the high density portion H and the EA material 1 described later The density of other parts (hereinafter sometimes referred to as non-dense parts) except for the skin layers 2a and 3a is 0.02 to 0.14 g / cm ^3, particularly 0.04 to 0.12 g / cm ^3. The difference in density between the high density portion H and the non-high density portion is preferably 0.01 to 0.13 g / cm ^3, particularly preferably 0.01 to 0.09 g / cm ³ .

  In this embodiment, the EA material 1 includes a surface layer 2 formed along at least a part of its outer surface, and an inner layer 3 formed on the inner side of the EA material 1 than the surface layer 2. Have. Each of the surface layer 2 and the inner layer 3 is formed by foaming a synthetic resin material having the same composition in a mold. In this embodiment, the surface layer 2 is formed before the inner layer 3, and the surface layer 2 and the inner layer 3 are integrated by inserting the molded surface layer 2 when the inner layer 3 is formed. ing. The details of the manufacturing method of the EA material 1 will be described later.

  In general, when a foamed synthetic resin material is foamed in a mold to produce a foamed molded body, the surface of the foamed molded body that is in contact with the inner surface of the mold is subjected to foam synthesis rather than inside the foamed molded body. The resin has a high density and a hard skin layer 2a is formed. In this embodiment, since the surface layer 2 is formed by a single die, the skin layer 2 a is formed on the entire surface of the surface layer 2. Therefore, by inserting the molded surface layer 2 at the time of molding the inner layer 3, the resin layer has a resin density on the surface layer 2 side of the boundary between the surface layer 2 and the inner layer 3 (that is, inside the EA material 1). A high skin layer 2a exists.

  In this embodiment, the skin layer 2 a of the surface layer 2 existing at the boundary between the surface layer 2 and the inner layer 3 constitutes a high-density portion H inside the EA material 1.

  In the portion of the surface of the inner layer 3 that is in direct contact with the inner surface of the mold at the time of molding, a skin layer 3a is formed as shown in FIG. Since the surface layer 2 becomes a heat insulating material in the portion where the intervening layer is interposed, the skin layer 3a is hardly formed. That is, there is almost no skin layer 3 a on the inner layer 3 side of the boundary between the surface layer 2 and the inner layer 3. However, in the present invention, the inner layer 3 may be formed before the covering layer 2, and the formed inner layer 3 may be inserted to form the surface layer 2. In this case, the skin layer 3 a is formed on the entire surface of the inner layer 3, and the skin layer 3 a of the inner layer 3 is disposed at the boundary between the surface layer 2 and the inner layer 3. The skin layer 3a of the inner layer 3 constitutes a high density portion H inside the EA material 1.

  In this embodiment, as shown in FIG. 2, the surface layer 2 is formed along the front end surface and the side peripheral surface of the EA material 1. In this embodiment, the surface layer 2 is formed continuously from the front end surface of the EA material 1 to the side peripheral surface, and the surface layer 2 extends over the entire front end surface and side peripheral surface of the EA material 1. Is formed. The rear end portion of the surface layer 2 formed along the side peripheral surface of the EA material 1 faces the rear end surface of the EA material 1 over the entire circumference. That is, at the rear end surface of the EA material 1, the peripheral edge portion is formed by the surface layer 2, and the inner layer 3 is exposed at the center side of the rear end surface.

  The arrangement of the surface layer 2 is not limited to this. For example, the surface layer 2 may be formed over the entire rear end surface of the EA material 1. The surface layer 2 may be provided only on a portion of the outer surface of the EA material 1 that needs reinforcement, and other than the rear end surface of the EA material 1, a portion where the surface layer 2 does not exist (the inner layer 3 is the EA material 1). There may be a portion exposed on the outer surface of. The surface of the inner layer 3 exposed on the outer surface of the EA material 1 and the surface of the surface layer 2 adjacent thereto may be arranged flush with each other as shown in FIG. Also good. The surface layer 2 may be formed across two or more surfaces of the front end surface, the side peripheral surface, and the rear end surface of the EA material 1 and is independent of each surface (so as not to straddle a plurality of surfaces). It may be formed.

  In addition, when forming the surface layer 2 on the side peripheral surface of the EA material 1, it is preferable to form the surface layer 2 in an endless circular shape over the entire periphery of the side peripheral surface as shown in FIG. By forming the surface layer 2 in this way, cracking and scattering of the EA material 1 can be effectively prevented when a load is applied to the front end surface or the rear end surface of the EA material 1.

  The thickness T (FIG. 2) of the surface layer 2 is preferably 15 to 25 mm, more preferably 15 to 20 mm.

<About the manufacturing method of the EA material 1 (1st example)>
In manufacturing the EA material 1, a high density portion H in which the density of the foamed synthetic resin is partially increased is provided therein. At that time, the high-density part H of the EA material 1 and the other parts are made of the same synthetic foamed synthetic resin.

  In this embodiment, as shown in FIGS. 4 (a) to (f), the surface layer 2 of the EA material 1 is molded using the surface layer molding die 10 before the inner layer 3 (the first layer 1). Layer molding step), and then, using the inner layer molding die 20, the molded surface layer 2 is inserted to mold the inner layer 3 (second layer molding step). At that time, the surface layer 2 and the inner layer 3 are formed by foaming the foamed synthetic resin raw material U having the same composition in the molds 10 and 20, respectively.

  As shown in FIGS. 4 (a) to 4 (c), the surface layer molding die 10 has a lower die 11 and an upper die 12. In addition, the metal mold | die 10 may have a core etc. as needed. The lower mold 11 is provided with a cavity 11 a made of a concave hole having a shape matching the outer shape of the EA material 1. In this embodiment, in the cavity 11a, the EA material 1 is molded with its tip side facing downward. That is, the front end surface of the EA material 1 is formed by the bottom surface of the cavity 11a of the lower mold 11, and the side peripheral surface of the EA material 1 is formed by the peripheral wall surface of the cavity 11a.

  From the central part of the cavity ceiling surface of the upper mold 12 of the surface layer molding die 10, a convex part 12 a having a shape matching the outer shape of the inner layer 3 is provided. In a state where the lower mold 11 and the upper mold 12 are clamped, a cavity space for molding the surface layer 2 exists between the inner surface of the cavity 11a and the outer surface of the convex portion 12a. A boundary surface between the surface layer 2 and the inner layer 3 (hereinafter, also referred to as a back surface of the surface layer 2) is formed by the outer surface of the convex portion 12a, and the convex portion 12a of the cavity ceiling surface of the upper mold 12 is formed. The rear end surface of the surface layer 2 (peripheral edge portion of the rear end surface of the EA material 1) is formed by a portion between the base end of the surface 11 and the upper edge of the peripheral wall surface of the cavity 11a. After demolding, a recess 2b (FIG. 4 (c)) formed by the convex portion 12a exists on the back surface side of the surface layer 2.

  As shown in FIGS. 4D to 4F, the inner-layer molding die 20 also has a lower die 21 and an upper die 22. The mold 20 may also have a core or the like as necessary. The lower mold 21 is provided with a concave hole 21a into which the molded surface layer 2 is fitted. The internal shape of the concave hole 21a is substantially the same as the internal shape of the cavity 11a of the lower mold 11 in the surface layer molding die 10. That is, the molded surface layer 2 is fitted into the concave hole 21a with the tip side of the EA material 1 facing downward.

  The cavity ceiling surface of the upper mold 22 of the inner layer molding die 20 has a shape that matches the rear end surface when the EA material 1 is completed. Thus, when the lower mold 21 and the upper mold 22 are clamped in a state where the molded surface layer 2 is disposed in the concave hole 21a of the lower mold 21, the cavity ceiling surface and the surface layer of the upper mold 22 are clamped. A cavity space for molding the inner layer 3 is present between the inner surface of the recess 2b on the back surface side of the two. By the cavity ceiling surface of the upper mold 22, the rear end surface of the inner layer 3 (the portion of the rear end surface of the EA material 1 that is closer to the center than the peripheral edge formed by the surface layer 2) is formed.

  When the EA material 1 is manufactured, first, as shown in FIG. 4 (a), the foamed synthetic resin raw material U for molding the surface layer 2 is formed in the cavity 11a of the lower mold 11 of the surface layer molding die 10. Inject from nozzle N. Next, as shown in FIG. 4 (b), the lower mold 11 and the upper mold 12 of the surface layer molding die 10 are clamped to foam the foamed synthetic resin material U. The foamed synthetic resin formed by foaming the raw material U fills the cavity space between the inner surface of the cavity 11a and the cavity ceiling surface of the upper mold 12 and the outer surface of the convex portion 12a, whereby the surface layer 2 is formed. . At this time, the foamed synthetic resin contacts the inner surface of the cavity 11a, the cavity ceiling surface of the upper mold 12 and the outer surface of the convex portion 12a, so that the skin layer 2a having a high density of the foamed synthetic resin is formed on the entire surface of the surface layer 2. Is formed. After the foamed synthetic resin is cured, as shown in FIG. 4 (c), the lower mold 11 and the upper mold 12 are opened to remove the surface layer 2 (the first layer molding step).

  Next, as shown in FIG. 4 (d), the molded surface layer 2 is set in the concave hole 21a of the lower mold 21 of the inner layer molding die 20, and the inner layer 3 is placed in the recess 2b on the back surface side. The foamed synthetic resin raw material U for molding is injected from the nozzle N. The foamed synthetic resin raw material U injected at this time has the same composition as that used for forming the surface layer 2 in the first layer forming step. Next, as shown in FIG. 4 (e), the lower mold 21 and the upper mold 22 of the inner layer molding die 20 are clamped to foam the foamed synthetic resin material U. The foamed synthetic resin formed by foaming the raw material U fills the cavity space between the inner surface of the recess 2b of the surface layer 2 and the cavity ceiling surface of the upper mold 22, thereby forming the inner layer 3 and the surface. The layer 2 and the inner layer 3 are integrated, and the entire molding of the EA material 1 is completed. After the foamed synthetic resin is cured, as shown in FIG. 4 (f), the lower mold 21 and the upper mold 22 are opened to remove the EA material 1 (the second layer molding step).

  Then, the EA material 1 is completed by performing the surface finish of the EA material 1 as needed.

  The surface layer 2 may be mass-produced in advance, and only the second layer forming step may be performed in an actual EA material manufacturing line, and the first layer forming step may be sequentially performed in one EA material manufacturing cycle. And the second layer forming step may be performed.

  In the above manufacturing method, separate molds are used in the first layer forming step and the second layer forming step. For example, the lower die 11 is made common throughout these steps, and only the upper dies 12 and 22 are used. May be exchanged between the first layer forming step and the second layer forming step.

<Effects produced by the EA material 1 and its manufacturing method>
In this EA material 1, since the high density part H is provided in the inside and this EA material 1 is reinforced by this high density part H, the EA material in which the high density part is not provided in the inside. Compared to, the shock absorption performance is excellent.

  In the EA material 1, the high density portion H and the other portions are made of the same synthetic foamed synthetic resin. Therefore, in order to improve the impact absorbing performance of the EA material 1, it is not necessary to prepare a member or material different from the EA material 1 itself, and the EA material 1 can be manufactured at a low cost. Further, in the EA material 1, since the high density portion H is provided in the foam molding process, it is not necessary to provide a reinforcing coating layer after the foam molding process, so that the manufacturing operation is simple. In addition, since the next process can be started immediately after the foam molding process, the manufacturing efficiency is high.

  In this embodiment, the EA material 1 has a multilayer structure including a surface layer 2 and an inner layer 3 on the inner side. Each of the surface layer 2 and the inner layer 3 is formed by foaming synthetic resin materials having the same composition in the molds 10 and 20. In this embodiment, when the EA material 1 is manufactured, the surface layer 2 is molded with the mold 10 before the inner layer 3, and then the molded surface layer 2 is formed with the mold 20. The inner layer 3 is formed by inserting. A skin layer 2 a having a high resin density is formed on the entire surface of the surface layer 2 previously molded with the mold 10 by the foamed synthetic resin constituting the surface layer 2 coming into contact with the inner surface of the mold 10. Therefore, by forming the inner layer 3 by inserting the surface layer 2, the skin layer 2 a having a high resin density is disposed at the boundary between the surface layer 2 and the inner layer 3, that is, inside the EA material 1. Will be. In this embodiment, the skin layer 2a constitutes the high density portion H. By doing in this way, the high density part H can be easily provided in the inside of the EA material 1 at low cost.

  In this embodiment, since the thickness T of the surface layer 2 is 15 to 25 mm, the impact absorbing performance of the EA material 1 can be sufficiently improved. In addition, when the thickness T of the surface layer 2 is 10 mm or less, the inner and outer skin layers 2a of the surface layer 2 may not have a required thickness, and a sufficient reinforcing effect may not be expected. When the thickness is 30 mm or more, the distance between the inner and outer skin layers 2a of the surface layer 2 is too far away, so that a sufficient reinforcing effect may not be expected.

<About the manufacturing method of the EA material 1 (2nd example)>
FIGS. 5A to 5F are cross-sectional views of a mold showing another method for manufacturing the EA material 1.

  In this embodiment, the mold 30 includes a lower mold 31, an upper mold 32, and a core 33 attached to the cavity inner surface of the upper mold 32 in the first layer forming step. The mold 30 may further have another core or the like as necessary. The lower mold 31 is provided with a cavity 31 a made of a concave hole having a shape matching the outer shape of the EA material 1. Also in this embodiment, the EA material 1 is molded in the cavity 31a with its tip side facing downward. That is, the front end surface of the EA material 1 is formed by the bottom surface of the cavity 31a of the lower mold 31, and the side peripheral surface of the EA material 1 is formed by the peripheral wall surface of the cavity 31a.

  The cavity ceiling surface of the upper mold 32 has a shape that matches the rear end surface when the EA material 1 is completed. The core 33 can be attached to and detached from the central portion of the cavity ceiling surface of the upper mold 32. The core 33 has a shape that matches the outer shape of the inner layer 3. When the lower mold 31 and the upper mold 32 are clamped with the core 33 attached to the cavity ceiling surface of the upper mold 32, the surface layer 2 is formed between the inner surface of the cavity 31a and the outer surface of the core 33. There is a cavity space for molding.

  A method for manufacturing the EA material 1 using the mold 30 will be described below.

  First, as shown in FIG. 5A, a foamed synthetic resin raw material U for molding the surface layer 2 is injected from the nozzle N into the cavity 31a of the lower mold 31 of the mold 30. Further, before the mold 30 is clamped, the core 33 is attached to the cavity ceiling surface of the upper mold 32. Next, as shown in FIG. 5B, the lower mold 31 and the upper mold 32 are clamped to foam the foamed synthetic resin material U. The foamed synthetic resin formed by foaming the raw material U fills the cavity space between the inner surface of the cavity 31 a and the cavity ceiling surface of the upper mold 32 and the outer surface of the core 33, thereby forming the surface layer 2. . At this time, the foamed synthetic resin comes into contact with the inner surface of the cavity 31a, the cavity ceiling surface of the upper mold 32, and the outer surface of the core 33, whereby the skin layer 2a having a high density of the foamed synthetic resin is formed on the entire surface of the surface layer 2. Is formed.

  After the foamed synthetic resin is cured, the lower mold 31 and the upper mold 32 are opened as shown in FIG. 5C, and the core 33 is removed from the cavity ceiling surface of the upper mold 32. At this time, the molded surface layer 2 is left in the cavity 31a (the first layer forming step).

  Next, as shown in FIG. 5 (d), a foamed synthetic resin material U for molding the inner layer 3 is injected from the nozzle N into the recess 2 b on the back surface side of the molded surface layer 2. The foamed synthetic resin raw material U injected at this time has the same composition as that used for forming the surface layer 2 in the first layer forming step. Next, as shown in FIG. 5 (e), the lower mold 31 and the upper mold 32 are again clamped to foam the foamed synthetic resin material U. The foamed synthetic resin formed by foaming the raw material U fills the cavity space between the inner surface of the recess 2b of the surface layer 2 and the cavity ceiling surface of the upper mold 32, whereby the inner layer 3 is molded and the surface The layer 2 and the inner layer 3 are integrated, and the entire molding of the EA material 1 is completed. After the foamed synthetic resin is cured, as shown in FIG. 5 (f), the lower die 31 and the upper die 32 are opened to remove the EA material 1 (the second layer forming step).

  Then, the EA material 1 is completed by performing the surface finish of the EA material 1 as needed.

  In the mold 30, since the lower mold 31 and the upper mold 32 are common in the first layer forming process and the second layer forming process, it is possible to reduce the mold cost.

[Second Embodiment]
FIG. 6 is a cross-sectional view of an EA material 1A as a foam molded member according to the second embodiment. FIG. 6 shows a cross section of the same portion as FIG.

  The EA material 1A in this embodiment includes a surface layer 2 formed along an outer surface thereof (a tip surface and a side circumferential surface of the EA material 1A in this embodiment), and the EA material more than the surface layer 2 1 has a plurality of inner layers 3A, 3B, 3C formed on the inner side. In this embodiment, a first inner layer 3A is formed adjacent to the surface layer 2, a second inner layer 3B is formed on the inner side of the EA material 1A, and further inside the EA material 1A. A third inner layer 3C is formed on the side. The shape and arrangement of the surface layer 2 in the EA material 1A are the same as those in the first embodiment.

  The first inner layer 3 </ b> A has a substantially similar shape to the surface layer 2, and is formed along the entire inner surface of the recess 2 b on the back surface side of the surface layer 2. That is, when the first inner layer 3A is viewed alone, the first inner layer 3A has a recess (reference number) on the back surface (boundary surface with the second inner layer 3B) side, like the surface layer 2. It has a shape with an abbreviation). The second inner layer 3B is substantially similar to the surface layer 2 and the first inner layer 3A, and is formed along the entire inner surface of the recess on the back surface side of the first inner layer 3A. That is, when the second inner layer 3B is viewed alone, the second inner layer 3B is also the back surface (boundary surface with the third inner layer 3C), like the surface layer 2 and the first inner layer 3A. It has a shape having a recess (not shown) on the side. The preferred range of the thickness of these inner layers 3A and 3B is the same as the preferred range of the thickness T of the surface layer 2 described above. The third inner layer 3C is filled with a recess on the back surface side of the second inner layer 3B. In addition, the shape and arrangement | positioning of inner layer 3A-3C are not limited to this. Two or more inner layers may be formed.

  In this EA material 1A, not only the boundary between the surface layer 2 and the first inner layer 3A, but also the boundary between the first inner layer 3A and the second inner layer 3B, and the second inner layer 3B A high density portion H is also provided at the boundary with the third inner layer 3C.

  As an example of the manufacturing method of the EA material 1A, a method using the mold 30 shown in FIG. 5 will be described.

  When the EA material 1A is manufactured using the mold 30, in addition to the surface layer forming core 33 for forming the surface layer 2, the first inner layer formation for forming the first inner layer 3A is performed. A working core (not shown) and a second inner layer forming core (not shown) for forming the second inner layer 3B are prepared. The first inner layer forming core has a shape that matches the inner surface shape of the recess on the back surface side of the first inner layer 3A, and the second inner layer forming core is the back surface of the second inner layer 3B. It has a shape that matches the inner shape of the recess on the side.

  In manufacturing the EA material 1, first, as in FIGS. 5A to 5C, the surface layer 2 is formed by the mold 30 with the surface layer forming core 33 attached to the upper mold 32. Molding (surface layer molding process).

  After forming the surface layer 2, the mold is opened, and the first inner layer forming core is attached to the upper mold 32 instead of the surface layer forming core 33. Then, a foamed synthetic resin material U for molding the first inner layer 3A is injected from the nozzle N into the recess 2b on the back surface side of the molded surface layer 2, and the mold is clamped to obtain the foamed synthetic resin material U. Foam. Thereby, the first inner layer 3A is formed on the back surface side of the surface layer 2, and the surface layer 2 and the first inner layer 3A are integrated (first inner layer forming step).

  After the molding of the first inner layer 3A, the mold is opened, and the second inner layer forming core is attached to the upper mold 32 instead of the first inner layer forming core. Then, a foamed synthetic resin raw material U for molding the second inner layer 3B is injected from a nozzle N into a recess on the back surface side of the molded first inner layer 3A, and the mold is clamped to form the foamed synthetic resin raw material U. Foam. Thereby, the second inner layer 3B is formed on the back surface side of the first inner layer 3A, and the first inner layer 3A and the second inner layer 3B are integrated (second inner layer forming step).

  After forming the second inner layer 3 </ b> B, the mold is opened, and the second inner layer forming core is removed from the upper mold 32. Then, a foamed synthetic resin raw material U for molding the third inner layer 3C is injected from the nozzle N into a recess on the back surface side of the molded second inner layer 3B, and the mold is clamped to perform the foamed synthetic resin raw material U. Foam. As a result, the third inner layer 3C is molded on the back surface side of the second inner layer 3B, and the second inner layer 3B and the third inner layer 3C are integrated to complete the entire molding of the EA material 1A. . After forming the third inner layer 3C, the mold is opened to remove the EA material 1A (third inner layer forming step).

  In this surface layer forming step, the skin layer 2a is formed on the entire surface of the surface layer 2, and in the first inner layer forming step, the skin layer 3a is formed on the back surface side of the first inner layer 3A. In the second inner layer forming step, A skin layer 3a is formed on the back side of the second inner layer 3B. These skin layers 2a and 3a are respectively the boundary between the surface layer 2 and the first inner layer 3A, the boundary between the first inner layer 3A and the second inner layer 3B, and the second inner layer 3B and the third inner layer. It exists in the boundary part with 3C, and comprises the high-density part H.

  In addition, said method is an example and the manufacturing method of EA material 1A is not limited to this. For example, as in the manufacturing method of FIG. 4, the surface layer molding die 10, the first inner layer molding die (not shown), the second inner layer molding die (not shown), and the third An inner layer molding die (not shown) is prepared, and the surface layer 2, the first inner layer 3A, the second inner layer 3B, and the third inner layer 3C are sequentially molded using dedicated dies, respectively. Also good. The lower mold may be shared, and only the upper mold may be a dedicated product for forming each layer.

  The other structure of this EA material 1A is the same as that of the EA material 1 in 1st Embodiment, and the same code | symbol as FIG. 1-3 in FIG. 6 has shown the same part.

  In the EA material 1A, since a plurality of layered high-density portions H exist inside, the shock absorbing performance is higher.

[Third Embodiment]
FIG. 7 is a cross-sectional view of an EA material 1B as a foam molded member according to the third embodiment. FIG. 7 shows a cross section of the same portion as FIG.

  In each of the above embodiments, the inner layers 3 and 3A to 3C are disposed at the center of the EA materials 1 and 1A when viewed from the front end side or the rear end side of the EA materials 1 and 1A. It is not limited to this.

  In the EA material 1B of FIG. 7, the inner layer 3 is formed at a position shifted from the center of the EA material 1B to the right side of FIG. 7, and on the left half side of the EA material 1B in FIG. The inner layer 3 is not present. Thereby, as for EA material 1B, the right-half side in the FIG. 7 has improved the shock absorption performance rather than the left-half side.

  As described above, when it is necessary to partially improve the shock absorbing performance of the EA material (or when it is sufficient to partially improve the shock absorbing performance), the inner layer 3 may be formed in that portion. .

[Example 1]
The length of one side of the rear end surface is 120 mm, the length of one side of the front end surface is 105 mm, the front end surface has a substantially truncated pyramid shape with a distance of 70 mm, and the thickness T of the surface layer 2 is 15 mm. is about 0.05 g / cm ³ resin density in the density section H, to produce the EA member 1 of the first embodiment the resin density in the non-high-density portion is about 0.04 g / cm ^3.

[Comparative Example 1]
FIGS. 8A to 8C are cross-sectional views of a mold showing a method for manufacturing the EA material 110 according to the comparative example, and FIG. 9 is a cross-sectional view of the EA material 110. FIG. 9 shows a cross section taken along line IX-IX in FIG. 8 (c).

  8 (a) to 8 (c), the same shape as in Example 1 and a uniform density inside (that is, the surface layer 2 and the inner layer 3 are not formed). The EA material 110 was manufactured. The mold 100 includes a lower mold 101 and an upper mold 102. The lower mold 101 is provided with a cavity 101a formed of a recessed hole having a shape matching the outer shape of the EA material 110 (= the outer shape of the EA material 1). In the cavity 101a, the EA material 110 is molded with its tip side facing downward. That is, the mold 100 has a structure in which the core 33 is omitted from the mold 30 in FIG.

  The manufacturing method of the EA material 110 is as follows.

  First, as shown in FIG. 8A, a foamed synthetic resin raw material U for molding the entire EA material 110 is injected from the nozzle N into the cavity 101a of the lower mold 101. Next, as shown in FIG. 8B, the lower mold 101 and the upper mold 102 are clamped to foam the foamed synthetic resin material U. The foamed synthetic resin formed by foaming the raw material U fills the cavity space between the inner surface of the cavity 101a and the cavity ceiling surface of the upper mold 102, whereby the EA material 110 is molded. At this time, the foamed synthetic resin comes into contact with the inner surface of the cavity 101a and the cavity ceiling surface of the upper mold 102, so that a skin layer 110a having a high resin density is formed on the entire surface of the EA material 110. The resin density is substantially uniform on the inner side of the EA material 110 than the skin layer 110a. After the foamed synthetic resin is cured, as shown in FIG. 8 (c), the lower mold 101 and the upper mold 102 are opened and the EA material 110 is removed.

  The foamed synthetic resin raw material U used for manufacturing the EA material 110 has the same composition as that used for manufacturing the EA material 1 of Example 1.

  In Comparative Example 1, the supply amount of the foamed synthetic resin raw material U at the time of molding the EA material 110 was set to the maximum amount capable of molding the EA material 110 without causing cracks in the EA material 110.

[Comparative Example 2]
The supply amount of the foamed synthetic resin raw material U to the mold 100 at the time of molding the EA material 110 is set to the minimum amount that allows the EA material 110 to be molded without causing a lack of thickness on the surface of the EA material 110. Except for this, the EA material 110 was produced in the same manner as in Comparative Example 1.

[Dynamic performance evaluation]
The EA materials 1 and 110 of Example 1 and Comparative Examples 1 and 2 were each subjected to a collision test machine 20 shown in FIG. In this test, each EA material 1,110 is installed on the support body 41 of the collision testing machine 40 with the front end side of the EA material 1,110 as the support body 41 side. 42 was collided at a speed of 8 m / sec, and the load applied to each EA material 1,110 and the strain generated in each EA material 1,110 were measured. The relationship between the load and strain is shown in the graph of FIG.

  As is clear from FIG. 11, the EA material 110 of the comparative example 2 having the lowest density among the comparative examples 1 and 2 and the example 1 has a plateau region (the load remains substantially constant after reaching a certain load). The load value in the region (P) in which the strain increases) is the smallest, and the shock absorbing performance is lower than those of Comparative Example 1 and Example 1. The EA material 110 of the comparative example 1 having a higher density than the comparative example 2 has a higher load absorption performance in the plateau region P than the comparative example 2, so that it can be seen that the shock absorbing performance is higher than that of the comparative example 2. The difference is not so big. In Comparative Example 2, the supply amount of the foamed synthetic resin raw material U at the time of molding the EA material 110 is the maximum amount that allows the EA material 110 to be molded without causing cracks inside the EA material 110. Therefore, even if the supply amount of the foamed synthetic resin raw material U at the time of molding the EA material 110 is increased, it is not expected to improve the impact absorbing performance.

  In Example 1, the method of changing the strain of the EA material 1 with respect to the load at the initial stage when the load starts to be applied to the EA material 1 is substantially the same as that of the EA material 110 of Comparative Examples 1 and 2. In Example 1, the load value in the plateau region P is higher than that in Comparative Example 1. Therefore, according to the present invention, it is possible to sufficiently improve the shock absorbing performance without substantially changing the deformation characteristics of the EA material 1 with respect to the load at the initial stage when the load is applied to the EA material 1. I understand that there is.

  Each of the above embodiments is an example of the present invention, and the present invention may have a configuration other than the above.

  For example, each of the above embodiments shows an application example of the present invention to an EA material for automobile interior and a manufacturing method thereof, but the present invention is also applied to other foam molded members and a manufacturing method thereof. Is possible.

1, 1A, 1B, 110 EA material 2 Surface layer 2a Skin layer 3, 3A, 3B, 3C Inner layer 3a Skin layer 10, 20, 100 Mold

Claims (7)

In a foam molded member made of foamed synthetic resin,
Inside the foam molded member is provided with a high density part in which the density of the foamed synthetic resin is partially higher than at least other parts excluding the surface of the foam molded member,
The foam-molded member, wherein the high-density portion and the other portions of the foam-molded member are composed of the same synthetic foam synthetic resin. The foam molded member according to claim 1,
A surface layer formed along at least a portion of the outer surface;
Having at least one inner layer formed on the inner side of the foam-molded member than the surface layer;
Each of the surface layer and the inner layer is formed by foaming a foamed synthetic resin material having the same composition in a mold,
One of the surface layer and the inner layer is formed before the other layer,
At the time of molding the other layer, the surface layer and the inner layer are integrated by inserting the molded one layer.
The foam-molded member, wherein the high-density portion is composed of a skin layer formed on the surface of the one layer when the one layer is molded.   The foam molded member according to claim 2, wherein the surface layer has a thickness of 15 to 25 mm.   The foam molded member according to any one of claims 1 to 3, wherein the foam molded member is made of rigid urethane foam.   5. The foam molded member according to claim 1, wherein the foam molded member is a shock absorber for automobile interior. 6. It is a manufacturing method of the foaming molding member according to any one of claims 1 to 5,
In the molding step of the foam molded member, the high density portion in which the density of the foamed synthetic resin is partially increased is provided inside the foam molded member,
A method for producing a foam-molded member, wherein the high-density part and the other part of the foam-molded member are formed of the same synthetic foamed synthetic resin. In Claim 6, the said foaming molding member is a thing of any one of Claim 2 thru | or 5,
In the molding process of the foam molded member,
A first layer forming step of forming the one of the surface layer and the inner layer before the other layer;
Inserting the formed one layer to form the other layer, and performing a second layer forming step of integrating the surface layer and the inner layer,
In the first layer forming step and the second layer forming step, the surface layer and the inner layer are formed by foaming a foamed synthetic resin material having the same composition in a mold, respectively. Manufacturing method of member.

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